1. Field of the Invention
The present invention relates to a method for ablating hyaluronan-based hydrogels with X-rays and a method for fabricating three-dimensional microchannels of hyaluronan hydrogels with the X-ray ablation technique.
2. Background of the Related Art
Phase transition triggered by external perturbation is quite important for “intelligent materials” and a key issue in diverse fields ranging from biomedicine to chemistry, physics, and materials science.
Hydrogels-three-dimensional networks of crosslinked polymer chains-exhibit transitions in response to perturbations such as electric fields, temperature changes, pH changes, concentration changes, enzymes, electron beams, sound, and light. Hydrogels are actively studied with the objective to develop new technologies to control fluidity, viscoelasticity, solvent volatility, optical transmission, ion transport, and other properties.
Hyaluronan (salt form of hyaluronic acid, HA) is an important extracellular and cell-surface associated polysaccharide. It is commonly synthesized as a large, negatively charged, linear polysaccharide that is composed of repeating disaccharide units of glucuronic acid and N-acetylglucosamine: [−β(1,4)−GlcUA−β(1,3)−GlcNAc−]n. HA has an important role in tissue homeostasis and biomechanical integrity via remarkable physicochemical characteristics such as viscoelastic and hygroscopic properties. These properties of HA lead to its widespread applications for bioengineered tissue scaffolds. Related physiological functions stimulate interest on its role in cell biology, pathology, immunology, and cancer research. The microfabrication of cell-laden HA architecture to resemble three-dimensional (3D) cellular microenvironments is also an important issue in HA. The HA molecular weight (MW) is, in general term, of critical importance because of its remarkable effects on cell activities. Although low MW HA, required for safe biomedical applications, is produced by enzymatic or non-enzymatic degradations, there are few reports on the safe, effective methods to fabricate 3D architectures of HA hydrogels.
As mentioned above, Hyaluronan hydrogels are promising materials for tissue scaffolds or cellular microenvironments, but it is still a great challenge to fabricate three-dimensional architectures.